Dear Mohsen saghafy,
Welcome to IMSLP/Petrucci Music Library! As a composer or other copyright proprietor, please take time to carefully review the Creative Commons Licenses and the IMSLP Performance Restricted Liecense. Generally speaking, the best version to employ for new works is the Creative Commons Attribution Non-commercial No Derivatives 3.0. This allows for free downloading of the items you post, yet prohibits anyone who downloads the files from IMSLP from selling the files (on Ebay, for example), or from giving public performances on an explicitly commercial basis, or making recordings of the work without written permission in advance from you, the composer and copyright owner. However, if you are affiliated with a performing rights society such as SOCAN (Canada), ASCAP, BMI or SESAC (USA), SACD, SACEM or SEAM (France), GEMA (Germany), PRS (UK), SGAE (Spain), SIAE (Italy), Artisjus (Hungary), ZAIKS (Poland), IPRO (India), JASRAC (Japan), or any of the myriad of similar agencies present in this Wikipedia listing, please note that at least some of these agencies refuse to honor the Creative Commons licenses. You should therefore seriously consider using the IMSLP Performance Restricted License for any works posted here if you are affiliated with a performance rights society.